"We're not doing this because we expect the results to be overturned or because there's a smoking gun," Dr Stein told The Daily Telegraph. "We are doing it because the American people deserve to have confidence in the voting system."

Mrs Clinton fared seven per cent worse in Wisconsin counties that used electronic voting machines rather than paper ballots, and despite a lack of any evidence, a cyber attack on the machines has been suggested as a possible explanation.

"This was a hacked election – party databases, individuals – there is no doubt there was a lot of hacking around this election and voting equipment is vulnerable to cyber attacks," Dr Stein said.

"The fact is the outcome was very close in those three states, a very small margin of victory. This is something positive we're doing to ensure the integrity of the voting system and restore peoples' faith."

While reversing the outcomes in all three states would hand the election to Mrs Clinton, Dr Stein said the recount effort was non-partisan. It would also not benefit her personally, as she won less than 1.4 million votes overall.

While Mr Trump has won 306 electoral college votes, compared to 232 for Mrs Clinton, the Democrat now has nearly two million more votes than him in the popular vote and pressure is mounting among liberals for a full investigation.